WASHINGTON -- Former congressman Jesse Jackson Jr. was charged Friday with misusing hundreds of thousands of campaign dollars for personal use -- as a long-running criminal investigation into his conduct neared an end.

His wife, Sandra, was charged with filing false tax returns in a separate criminal indictment, released Friday by federal authorities.

Jackson and his attorneys have been in plea negotiations with the U.S. Justice Department, multiple media reports indicate. The Associated Press reported Friday that an attorney for Sandra Jackson said she had signed a plea deal with authorities.

Jackson, 47, resigned from Congress in November. He sought treatment twice for bipolar disorder at the Mayo Clinic and had been on medical leave since June when he stepped aside. The namesake son of the civil rights leader, Jackson was heralded as a rising Democratic Party star when he was first elected in 1995.

The indictment details funds splurged on a children's furniture, a $43,350 gold-plated men's Rolex watch, $5,150 worth of fur capes and parkas and thousands more on memorabilia from martial arts master Bruce Lee, hats and guitars that once belonged to singer Michael Jackson -- along with memorabilia linked to slain civil rights leaders Martin Luther King Jr. and Malcolm X.

Although Jackson cited his health as a reason for his resignation, he had acknowledged for the first time that he was under federal investigation for allegedly misusing campaign funds to decorate his home and buy an expensive watch for a friend.

In his resignation letter, Jackson said that he was working with authorities to resolve the case. He said he was "doing my best to address the situation responsibly, cooperate with the investigators and accept responsibility for my mistakes."

Jackson also had been the subject of a long-running House Ethics Committee investigation stemming from allegations that he offered to raise money for then-Illinois governor Rod Blagojevich in exchange for appointment to the U.S. Senate to succeed Barack Obama after he was elected president in 2008. Jackson denied wrongdoing in that investigation.

More than a dozen candidates are running in the special election to succeed Jackson in the House. The Chicago-based district is heavily Democratic. The primary is Feb. 26.

Criminal prosecutions against current or former members of Congress for violating federal campaign-finance laws are "rare," said Kenneth Gross, a Washington lawyer and campaign-finance expert. "It should be rare," he said. "Most cases fall within the civil remedies because generally there's not a willful intent to violate the law."

In Jackson's case, "if the allegations are true, and the campaign money was spent on personal items, it's easier for the prosecution to make a case," he said. "It's hard to say, 'This expensive watch is a campaign expense.' "

Jackson's medical disorder, his resignation from Congress and cooperation with prosecutors "could be factors in mitigating" the amount of any prison time prosecutors seek, Gross said.